[war1025]

> Lots of grocery store meat that you buy "fresh" was killed x number of days ago.

Most beef, at least that you buy locally from a butcher who got the animal from a local farmer, is dry aged in a cooler for 10 - 14 days after slaughter. [1]

I don't know whether that's true for mass-market meat or not. But it's very common to let meat age before eating it.

[1] https://en.wikipedia.org/wiki/Beef_aging